Personally I don't trust any third-party registry cleaning programs, especially from unknown sources, for determining that my registry has errors that need to be repaired or deleted. If you were to do a registry scan w/ ten different so-called registry cleaning / repair programs, you'd get ten different scan results. So being that the results would be different based on the program, which one would you trust to clean your registry?
A guy posted here some time ago that used the built-in registry cleaner in CCleaner, after which on reboot Windows refused to load either to normal mode or safe mode. He hadn't made a backup beforehand, and had important data on the drive that he couldn't afford to lose.